#include<bits/stdc++.h>
using namespace std;
const int MAXN=1e3;
typedef long long LL;
struct bign {
	int len, s[MAXN];
	bign () {
		memset(s, 0, sizeof(s));
		len = 1;
	}
	bign (int num) {
		*this = num;
	}
	bign (const char *num) {
		*this = num;
	}
	bign operator = (const int num) {
		char s[MAXN];
		sprintf(s, "%d", num);
		*this = s;
		return *this;
	}
	bign operator = (const char *num) {
		for(int i = 0; num[i] == '0'; num++) ;
		len = strlen(num);
		for(int i = 0; i < len; i++) s[i] = num[len-i-1] - '0';
		return *this;
	}
	bign operator + (const bign &b) const {
		bign c;
		c.len = 0;
		for(int i = 0, g = 0; g || i < max(len, b.len); i++) {
			int x = g;
			if(i < len) x += s[i];
			if(i < b.len) x += b.s[i];
			c.s[c.len++] = x % 10;
			g = x / 10;
		}
		return c;
	}
	void clean() {
		while(len > 1 && !s[len-1]) len--;
	}
	bign operator * (const bign &b) {
		bign c;
		c.len = len + b.len;
		for(int i = 0; i < len; i++) {
			for(int j = 0; j < b.len; j++) {
				c.s[i+j] += s[i] * b.s[j];
			}
		}
		for(int i = 0; i < c.len; i++) {
			c.s[i+1] += c.s[i]/10;
			c.s[i] %= 10;
		}
		c.clean();
		return c;
	}
	string str() const {
		string res = "";
		for(int i = 0; i < len; i++) res = char(s[i]+'0')+res;
		return res;
	}
};
ostream& operator << (ostream &out, const bign &x) {
	out << x.str();
	return out;
}
bign a[500];
int main(void){
    int n;cin>>n;
    a[1]=0;a[2]=1;
    for(int i=3;i<=n;i++){
        a[i]=(a[i-1]+a[i-2])*(i-1);
    }
    cout<<a[n]<<"\n";
}
